Many electromechanical devices employ two or more separate electrical actuators in their operation. For instance, some fuel injectors use two independently controllable solenoids to control such performance parameters as injection timing and fuel pressurization. While the use of two separately controllable solenoids can improve injector performance, there has been some hesitation in the industry to adopt two or more solenoids in a fuel injector because the benefits do not always outweigh the costs. In addition to financial costs, there are the increased complexity and hardware required to provide each solenoid with a separate electrical circuit. Two separate electrical circuits also tend to undermine robustness and long term reliability in most fuel injector applications. On the other hand, use of a single solenoid to control two separate electrical actuators can lead to a highly sensitive system that requires "glitch" detection in the controller as well as very tight tolerances on the injector assembly.
The present invention is directed to these and other problems associated with the use of two or more electrical actuators in an electromechanical device, such as a fuel injector.